DMDM

Hi all, I graduated with a BSc in Econ and Finance degree a few years ago from one of the top 3 universities in HK, and is planning to apply for Operations Research/Computer Science Master's programs (mainly targeting top US schools, with UK schools as secondary options). A professor (associate professor grade) who taught me financial statistics (with topics in probability functions, regression models and time series models) has agreed to write LORs for me. I have also asked the head of the econ department who taught me intermediate micro econ theory to write me LORs (pending his confirmation). I'd like to know whom should I ask as the third person to write me LORs? Below is a summary of the relevant courses I took: 1. Elementary Calculus and Linear Algebra: Topics in matrices, differentiation and integration etc. Taught by an associate professor; the class size was too large so most likely he wouldn't recognize me. 2. Elementary Statistics: Topics in probability, sampling distribution, hypothesis testing, regression etc. Taught by a lecturer; again the class size was too large so most likely she wouldn't recognize me. 3. Math for economics: Topics in linear models, optimization and multivariable calculus. Taught by a visiting scholar; while the class size was small, I did not have much interaction with her so again most likely she wouldn't recognize me. 4. Econometrics: Topics in simple and multiple linear regression, instrumental variables, simultaneous equations models, limited dependent variables etc. Taught by an associate professor at UBC (during my exchange study); again the class size was too large so most likely he wouldn't recognize me. 5. VBA programming: Topics in excel formulas, VBA programming fundamental concepts (for loop, while loop, object-oriented programming etc.). Taught by a lecturer; again the class size was too large so most likely he wouldn't recognize me. I also contemplated asking lecturers who taught me finance courses in derivatives pricing, portfolio theory, and financial management, respectively, since these courses also involve certain level of math, but I am not sure as to whether LORs from finance professors weight much for OR/CS master's programs. For all of the courses mentioned above, I either got grades of A+ or A. Any help and advice would be much appreciated. Thanks you so much!